1. Field of the Invention
The present invention relates to a forging die, and a method and an apparatus for controlling the same, in which a forging material is arranged in a cavity so that it may be forged in accordance with a pressurizing action of a punch.
2. Description of the Related Art
A forging die has been hitherto known, which is used to forge a forging material into a predetermined shape such that the forging material is inserted into a cavity which is formed by an upper die and a lower die joined to one another, and a pressurizing force is applied to the forging material by the aid of a punch.
The present applicant has suggested a forging die which is provided with a buffering mechanism for absorbing a residual displacement amount corresponding to a range from abutment of a punch against a lower die to arrival at a bottom dead center (Japanese Laid-open Patent Publication No. 11-169996).
The buffering mechanism includes a piston which is provided displaceably along a pressure chamber charged with a pressure oil. The buffering mechanism functions to preferably absorb the residual displacement amount of the punch by using the pressure oil charged in the pressure chamber in accordance with a displacement action of the piston.
A general object of the present invention is to provide a method and an apparatus for controlling a forging die, in which a high pressure is applied without generating any surge pressure, and a buffering function is preferably effected to absorb the forming load by using a pressure fluid having a high discharge speed.
A principal object of the present invention is to provide a method and an apparatus for controlling a forging die, in which if no forging material is charged in a cavity, the die is prevented from any damage even when an upper die and a lower die make abutment so that the durability of the die is improved.
Another object of the present invention is to provide a forging die, in which any strain of the die due to any stress is reduced to improve the durability of the die, and the cost of the die is lowered.
Still another object of the present invention is to provide a forging die, in which the die is allowed to have a simplified structure to improve the dividability, and the number of parts to be exchanged due to secular change is made as small as possible so that the cost may be reduced.
Still another object of the present invention is to provide a forging die, in which any stress concentration, which would be otherwise caused by tensioning, is suppressed to improve the durability of the die, and thus the cost of the die can be lowered.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.